Combined punch press and cutting torch with workpiece supporting means

ABSTRACT

A workpiece is shifted forwardly and rearwardly beneath a punch and a transversely spaced cutting torch by a work table formed with a comparatively wide fore-and-aft extending throat for accommodating a die and a duct which underlie the punch and the torch, respectively. The throat is partially filled by platforms which normally support the overlying portions of the workpiece to reduce deflection thereof but which are adapted to be automatically moved out of the way of the rear of the table when the table is shifted forwardly.

BACKGROUND OF THE INVENTION

This invention relates to a punch press for forming holes in aworkpiece. The invention more particularly relates to apparatus in whicha melting tool such as a plasma-arc torch acts in conjunction with thepunch press. The combination of a punch press and a plasma-arc torch isdisclosed in Brolund et al U.S. application Ser. No. 735,087, filed Oct.22, 1976, now U.S. Pat. No. 4,063,059 entitled Punch Press With CuttingTorch and assigned to the assignee of the present invention.

As disclosed in the Brolund et al application, the punch press includesa reciprocating punch which coacts with an underlying die to formcomparatively small and substantially regularly shaped holes in theworkpiece. The plasma-arc torch is spaced transversely from the punchand is used to cut sections from the workpiece and to form large andirregularly shaped holes in the workpiece. The torch operates byionizing a column of gas with an electric arc to produce temperatures upto 30,000° F. As the high velocity, high temperature plasma streamstrikes the workpiece, the heat instantly melts the metal while thestream blows the molten metal downwardly away from the workpiece. A ductis disposed just beneath the workpiece in alinement with the torch andserves to collect the molten metal.

The workpiece is supported on a table which is adapted to be moved in afore-and-aft direction on a frame or a bed in order to shift theworkpiece to various fore-and-aft positions relative to the punch andthe torch. Carried on the rear of the table are one or more clampshaving upper and lower jaws for gripping the rear edge of the workpiece.The clamps may be shifted transversely on the table to move theworkpiece to various transverse positions beneath the punch and thetorch.

To enable the workpiece table to move forwardly past the die and theduct, the table is formed by two conjointly movable sections which arespaced apart so as to define a fore-and-aft extending throat in thetable. As a result of the throat, the table may be moved forwardly topositions in which the two table sections straddle the die and the duct.Being required to accommodate both the die and the transversely spacedduct, the throat is relatively wide and thus a gap of considerable widthis left between the two table sections so that the portion of theworkpiece overlying the throat is not supported by the table sections.

SUMMARY OF THE INVENTION

The primary aim of the present invention is to provide a new andimproved punch press of the above type in which one or more platformsare uniquely disposed within the throat between the table sections andare adapted to support the overlying portions of the workpiece so as toreduce deflection of the edge portions and any thin projecting portionsof the workpiece and thereby prevent such portions from engaging andbeing bent by the sides of the table sections.

Another object is to provide platforms which normally are adapted tosupport the workpiece but which automatically move out of the way of therear of the table when the table is moved forwardly.

A more detailed object is to provide a workpiece-supporting platformlocated rearwardly of the die and duct and adapted to swing downwardlyout of the way of the rear of the table, and further to provide a secondplatform located between the die and the duct and adapted to slideforwardly out of the way of the rear of the table.

These and other objects and advantages of the invention will become moreapparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary perspective view of an exemplary punch presshaving a plasma-arc torch and incorporating the new and improvedfeatures of the present invention.

FIG. 2 is an enlarged fragmentary cross-section taken substantiallyalong the line 2--2 of FIG. 1.

FIG. 3 is a fragmentary cross-section taken substantially along the line3--3 of FIG. 2.

FIG. 4 is a view similar to FIG. 3 but shows certain parts in movedpositions.

FIG. 5 is an enlarged fragmentary cross-section taken substantiallyalong the line 5--5 of FIG. 3.

FIG. 6 is an enlarged plan view of certain parts as viewed along theline 6--6 of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is illustrated in the drawings in conjunction witha punch press 10 which may be used for forming holes in a workpiece 11which herein is shown as a flat piece of sheet metal. The press includesa conventional C-shaped support or frame 13 housing a hydraulic actuator(not shown) which is adapted to reciprocate a punch 14. A die assembly15 underlies the workpiece and is disposed in vertical alinement withthe punch to coact with the latter and form a hole in the workpiece whenthe punch is shifted downwardly. The die assembly is supported on anunderlying bed 16 which constitutes part of the frame of the press.

To increase the versatility and productivity of the press 10, a metalmelting tool which herein is in the form of a plasma-arc torch 25 isattached to one side of the C-frame 13 and is adapted to cut large andirregularly contoured shapes out of the workpiece. Plasma-arc torchessuch as the torch 25 are commercially available as, for example, fromThermal Dynamics Corporation of West Lebanon, New Hampshire. Basically,such a torch includes a tip defining a small orifice through which anionized column of gas and an electric arc are forced. The plasma streamand the electric arc (hereinafter called the plasma-arc) are dischargedfrom the orifice at high velocity and produce extremely hightemperatures to cause instantaneous melting of the underlying portion ofthe workpiece 11 and to blast the molten metal downwardly from theworkpiece. This process makes a clean, high speed cut with little slagformation and is generally accepted as the preferred method of cuttingsections up to 6" thick from stainless steel and non-ferrous or cladmetals that are not easily cut by oxygen fuel gas processes.

With the plasma-arc torch 25 mounted on the press frame 13, the punch 14can be used to form small and regularly shaped holes in the workpiece 11while the torch can be used in place of a nibbling operation to rapidlycut larger holes and to form irregularly shaped cuts or openings. Also,the punch may be used to form a starting hole in the workpiece sectionor sections to be cut by the torch and thereby eliminate direct downwardimpingement of the plasma-arc on solid metal. This reduces the danger ofthe torch becoming plugged by metal which otherwise might splatterupwardly upon initial contact of the plasma-arc with the workpiece 11.

During operation of the torch 25, hot fumes and molten metal areproduced. The molten metal and the fumes are directed into an uprightduct 30 (see FIGS. 2 and 4) secured to the bed 16 and located invertical alinement with the tip of the torch 25, the duct thus beingspaced transversely from the die 15. Herein, the duct is made of sheetmetal and its upper end is formed with a central rectangular opening 36(FIG. 6) which is coaxial with the tip of the torch 25. The upper end ofthe duct is located in contact with the lower side of the workpiece 11.As shown in FIG. 1, the duct leads downwardly to a receptacle such as abucket 43 for collecting the molten metal blown downwardly from theworkpiece 11. The bucket 43 is attached releasably to the lower end ofthe duct and is located within an opening in a panel 47 which covers thefront of the bed 16. Smoke and other fumes resulting from operation ofthe torch 25 are disposed of by means of a vacuum system or unit (notshown) which communicates with the duct 30 by means of a flexible hose(not shown) which is connected to the lower portion of the duct abovethe bucket 43. Reference may be had to the aforementioned Brolund et alapplication for a detailed disclosure of the construction and operationof the vacuum system.

To move the workpiece 11 to various positions beneath the punch 14 andthe torch 25, the workpiece is supported on a table 50 which, in turn,is mounted to move back and forth in the direction of the arrow 51(FIG. 1) on the underlying bed 16. The table actually is formed by leftand right sections 53 and 54 which are spaced transversely from oneanother so as to leave a fore-and-aft extending space or throat 55(FIGS. 1 and 2) located between the two sections and opening out of thefront of the table. The throat 55 is alined with the die 15 and the duct30 and is wider than the transverse dimension between the right-handside of the die and the left-hand side of the duct. As a result of thethroat, the table 50 may be driven forwardly to positions in which thetwo table sections 53 and 54 straddle the die and the duct and thusvirtually all areas of the workpiece 11 may be moved beneath the punch14 and the torch 25. The two table sections move in unison with oneanother and are driven back and forth on the bed 16 by a screw mechanism(not shown) located beneath the table.

The table 50 supports anti-friction balls 56 which allow the workpiece11 to move in the transverse direction (i.e., left to right or viceverse) across the table and beneath the punch 14 and the torch 25. Toeffect such movement, two clamps 57 (FIGS. 1 to 3) are carried on theback of the table, grip the rear margin of the workpiece and are adaptedto be driven transversely along the table to shift the workpiece. Eachclamp includes upper and lower horizontally extending jaws whichrespectively engage the upper and lower sides of the workpiece. Theclamps are mounted on a carriage 59 (FIGS. 2 and 3) which is guided bytransversely extending rods 60 located on a cross member 61 connected toand extending along the rear of the table and spanning the throat 55between the table sections 53 and 54. A screw mechanism 63 (FIG. 3) isoperably connected between the cross member 61 and the carriage 59 andshifts the carriage on the cross member to move the clamps 57 and theworkpiece 11 transversely relative to the table.

In accordance with the present invention, platforms 65, 66 and 67 arelocated within the throat 55 between the table sections 53 and 54 andsupport those portions of the workpiece 11 which overlie the throat soas to reduce vertical deflection of the overlying workpiece andparticularly to reduce deflection of the edge portions of the workpieceand of thin portions which may be left as a result of the cuttingoperation. As the table 50 moves forwardly to position the rear portionof the workpiece beneath the punch 14 and/or torch 25, the platforms 65,66 and 67 are automatically moved out of the way of the rear portion ofthe table so as to enable the table to shift forwardly as necessary.

More specifically, the platforms 65 and 66 are positioned rearwardly ofthe die 15 and the duct 30 and are located in fore-and-aft spacedrelationship within the throat 55. Each of the platforms 65, 66 extendsacross substantially the entire width of the throat and is supported onthe upper ends of a pair of arms 70 and 71 (FIGS. 2 and 3) which extendupwardly and forwardly from the bed 16 and whose lower end portions areconnected pivotally to the bed as indicated at 73 to swing about ahorizontal axis. A cantilevered leaf spring 74 is located between thearms of each pair and its upper end portion bears against a rod 75extending transversely between the arms, the lower end portion of thespring being secured to the bed. The springs urge the platforms 65 and66 upwardly to active positions in which the upper sides of theplatforms either engage the underside of the workpiece 11 or are locatedvery closely adjacent the underside of the workpiece. Accordingly, theplatforms 65 and 66 normally support these portions of the workpiecethat overlie the comparatively wide throat 55 and thus the platformsprevent the edge portions of a thin workpiece from deflecting downwardlyinto the throat and prevent those portions from engaging and being bentby the sides of the table sections 53 and 54 when the workpiece isadvanced transversely. The platforms also prevent deflection of narrowand flexible sections which may be left in the workpiece as a result ofthe cutting operation.

As a result of being pivotally mounted, the platforms 65 and 66 arecapable of swinging downwardly and moving to inactive positions out ofthe way of the rear cross member 61 of the table 50 when the latter isshifted forwardly. As shown in FIGS. 2 and 3, a bar 76 is attached toand extends rearwardly from the cross member and is located infore-and-aft alinement with the arms 70 of the platforms 65 and 66.Carried on the bar 76 are abutment means which herein are in the form offour rollers 77 journaled on and spaced along the bar.

When the table 50 is shifted forwardly, the leading roller 77 engages ashallow depression 79 (FIGS. 3 and 4) formed in the arm 70 of the rearplatform 65, such engagement occurring prior to engagement of theplatform or the arms 70 and 71 by any other part of the table. As thetable continues forwardly, the leading roller 77 cams the arm 70downwardly (see FIG. 4) to swing the rear platform 65 downwardly to aninactive position in which the platform is located below the crossmember 61 so as to permit the cross member to move forwardly past theplatform. With continued forward movement of the table, the leadingroller 77 passes through a notch 80 (FIG. 2) in the platform 65 whilethe trailing rollers on the bar 76 successively engage the arm 70 tohold the platform in its downwardly cammed position. The leading rollerthen engages a depression 81 in the arm 70 of the forward platform 66 asshown in full lines in FIG. 4 and ultimately cams that platformdownwardly as shown in dotted lines. Accordingly, the platforms 65 and66 are automatically moved out of the way of the rear cross member 61 ofthe table 50 as the latter is shifted forwardly. When the table isretracted rearwardly, the rollers 77 move off of the arms 70 to enablethe forward platform 66 and then the rear platform 65 to swing upwardlyto their active positions shown in FIG. 3.

The platform 67 is generally L-shaped and includes a fore-and-aftextending portion 85 (FIG. 2) normally located between the die 15 andthe duct 30 and a transversely extending portion 86 located in front ofthe duct. In keeping with the invention, the platform 67 is supported onthe bed 16 to slide between a rear position shown in full lines in FIG.4 and a forward position shown in dotted lines. For this purpose, a pairof L-shaped guides 87 (FIG. 5) are attached to the lower side of thefore-and-aft extending portion 85 of the platform 67 and straddle afore-and-aft extending bar 89 which is connected to the bed 16. Acontractile spring 90 is connected at its forward end to one of theguides and at its rear end to a depending finger 91 on the rear portionof the bar 89. The spring 90 normally urges the platform 67 to itsrearward position but enables the platform to slide forwardly on the bar89 and out of the way of the rear of the table 50 when the latter isshifted to its extreme forwardmost position.

To slide the platform 67 forwardly, a second abutment means is attachedto the rear cross member 61 of the table 50 and is in the form of asmall table section 95 (FIGS. 4 and 6) which is located within thethroat 55 and which projects a short distance forwardly of the crossmember 61. The rear table section 95 is of such width as to be capableof moving between the die 15 and the duct 30 and carries anti-frictionballs 96 (FIG. 6) which are disposed at the same elevation as the balls56 of the main table sections 53 and 54. Similarly located balls 97 aresupported on the platform 67 to reduce friction when the workpiece 11 isshifted by the clamps 57 and also when the platform moves forwardly orrearwardly beneath the workpiece.

The platform 67 normally is disposed in its rear position shown in FIG.2 and thus supports and reduces deflection of those portions of theworkpiece 11 located between the die 15 and the duct 30 and located justforwardly of the duct. As the table 50 is shifted toward its extremeforwardmost position, the front edge of the rear table section 95engages the rear edge of the platform 67 and pushes the platformforwardly out of the way of the rear of the table 50 and out of the wayof any clamp 57 which might happen to be positioned immediately over therear table section (see FIG. 6). With continued forward shifting of thetable, the rear table section 95 moves between the die 15 and the duct30 and occupies the space formerly occupied by the fore-and-aft portion85 of the platform 67 so as to support and prevent deflection of theoverlying portion of the workpiece 11 during cutting. When the table 50shifts rearwardly, the rear table section 95 retracts away from theplatform 67 to enable the spring 90 to return the platform rearwardly toits normal position.

From the foregoing, it will be apparent that the present inventionbrings to the art new and improved punch press and cutting torchapparatus in which the platforms 65, 66 and 67 partially fill the throat55 between the table sections 53 and 54 and reduce deflection of theworkpiece 11, the invention serving to particular advantage when acomparatively thin and flexible workpiece is being handled. Theplatforms are automatically moved out of the way of the rear of thetable 50 when the table is shifted forwardly and then automaticallyreturn to their normal positions when the table is retracted and thusthe platforms do not restrict the freedom of movement of the table.

We claim:
 1. A punch press comprising a frame and a verticallyreciprocable punch, a die on said frame in underlying relation with saidpunch and adapted to coact with said punch to form a hole in anintervening workpiece when said punch is advanced downwardly, a metalcutting tool mounted in a horizontally stationary position on said framein transversely spaced relation with said punch and operable to emitdownwardly directed energy for melting said workpiece, an upright ducton said frame beneath said workpiece and alined with said tool wherebymolten metal from said workpiece is directed downwardly into said duct,a table for supporting said workpiece and movable back and forth in afore-and-aft direction on said frame to locate said workpiece in variousfore-and-aft positions beneath said punch and said tool, said tablebeing formed by a first section located on one side of said die and saidduct and by a conjointly movable second section located on the oppositeside of said die and said duct, there being a fore-and-aft extendingthroat between said table sections to permit said table to moveforwardly to positions in which said table sections straddle said dieand said duct, first and second platforms each having an upper surfacefor supporting said workpiece, each of said platforms being disposedbetween said table sections and located within said throat in at leastsome positions of said table, said first platform being locatedrearwardly of said die and said duct, said second platform being locatedbetween said die and said duct, abutment means on the rear portion ofsaid table and successively engageable with said first and secondplatforms as said table is moved forwardly, and means mounting eachplatform on said frame for movement relative to said table and saidframe and permitting each platform to move out of the way of saidabutment means when said platform is engaged by said abutment means. 2.A punch press as defined in claim 1 in which said mounting means supportsaid first platform to swing downwardly and support said second platformto slide forwardly when said platforms are engaged by said abutmentmeans, and resilient means connected to said frame and urging said firstplatform upwardly and said second platform rearwardly.
 3. A punch pressas defined in claim 2 in which said second platform is generallyL-shaped and includes a first portion located between said die and saidduct and further includes a transversely extending second portionlocated in front of said duct.